The impacts of AMPEP K+ (Ascophyllum marine plant extract, enhanced with potassium) on the growth rate, carrageenan quality, and percentage incidence of the damaging epiphyte Neosiphonia apiculata on four strains of the commercially important carrageenophyte Kappaphycus, as developed by micropropagation techniques

Four strains of Kappaphycus spp. (viz. K. alvarezii-tambalang brown and green, K. striatus-sacol green) and K. malesianus (aring-aring) were grown in Semporna, Sabah, for three consecutive growth cycles from August 2018 to January 2019, each for a duration of 45 days. The study was established in order to determine the impacts of a commercially produced phyco-stimulant: Ascophyllum marine plant extract powder, enhanced with potassium (i.e., AMPEP K+) on micropropagated Kappaphycus strains on the mean daily growth rate (DGR), quality characteristics of extracted, refined carrageenan from the harvested biomass (i.e., yield, viscosity, and gel strength), and the percentage incidence of the damaging, endophytic Neosiphonia apiculata, while in open water cultivation. Results showed that the AMPEP K+-treated thalli were significantly different (P < 0.01), in terms of the three major assessment criteria used in this study. Amongst the four cultivars, and under the conditions tested, K. striatus was the most resistant to the incidence of N. apiculata, particularly when treated with AMPEP K+. The use of the brown seaweed-derived extract, as a phyco-stimulant, applied to a commercially cultivated, red seaweed for the promotion of thallus growth, reduction of biotic stress caused by endophytes, and important improvements to commercially valuable traits, such as carrageenan quality, are encouraging. It is recommended that these protocols should be adopted in crop management to assist the Malaysian seaweed industry.